The alternator mounted on the vehicle generally generates power by an engine torque generated by an engine. That is to say, power generation of the alternator becomes a load when the engine operates. Therefore, an alternator load torque generated by the power generation of the alternator acts on the vehicle. Herein, the alternator is connected to a battery mounted on the vehicle. Therefore, the battery is charged by the power generation of the alternator. In general, charge control to charge the battery is performed by control of the alternator by the alternator controlling apparatus.
Herein, devices such as a wiper, a headlight, electric power steering (EPS) and a variable gear ratio steering (VGRS) mounted on the vehicle are connected to the battery as an electrical load. The electrical load fluctuates by operation of the devices and a voltage in an electric system of the vehicle including the battery and the electrical load fluctuates. Especially, when the electric power steering (EPS) and the variable gear ratio steering (VGRS) operate, the electrical load largely fluctuates and the voltage in the electric system of the vehicle tends to fluctuate largely. In the alternator controlling apparatus, a target power generation current value of the alternator as the control amount is set based on deviation between the battery voltage and the target voltage being the reference physical amount as the control reference of the alternator, and the power generation current of the alternator is changed. Therefore, the power generation torque of the alternator, that is to say, the alternator load torque relative to the engine fluctuates by the fluctuation of the electrical load.
Therefore, the conventional technique to suppress the fluctuation of the alternator load torque is suggested. For example, the Patent Document 1 discloses to balance out decrease in an alternator drive torque (alternator load torque) by increase in generation torque of the engine (engine torque) by fuel injection from fuel cutoff during deceleration. That is to say, the Patent Document 1 discloses the technique to balance out the fluctuation of the alternator load torque by the engine torque. Also, as in the Patent Document 2, the technique to control an auxiliary machine with delay in consideration of delay in engine response in order to suppress the fluctuation of the engine torque by fluctuation of an auxiliary machine drive torque is disclosed. Also, as disclosed in the Patent Documents 3 and 4, there is the alternator load torque disclosed in the Patent Document 2. The technique to suppress vibration by controlling target drive force is also disclosed.
Patent Document 1: Japanese Patent Application Laid-open No. 2006-94624
Patent Document 2: Japanese Patent Application Laid-open No. 2006-335097
Patent Document 3: Japanese Patent Application Laid-open No. 2006-298293
Patent Document 4: Japanese Patent Application Laid-open No. 2006-347254